Field of the Invention
The present invention relates to switching method and a video transmission system for a real-time video content. More specifically, the present invention relates to a video receiver configured to selectively switch and output multiple video streams distributed through an IP network, and a method for providing video streams to the video receiver from the network used for the video transmission.
Description of the Related Art
Broadcasting stations receive many video contents from multiple facilities, for example, stadiums, other broadcasting stations, production trucks, and the like. Moreover, broadcasting stations themselves also produce multiple video contents inside the stations. In order to distribute such many video contents, the videos have to be switched at real-time timings.
There are roughly two schemes for switching video contents. First, the first switching scheme for video is the scheme in which a currently distributed video content is switched to another video content that is different content from the currently distributed video content. By this scheme, for example, a video content captured by a camera a is switched to a video content captured by a camera b.
The second switching scheme for video content, a video content in a currently-active system is switched to a video content in a backup system in a case where there are redundant transmission paths for video contents. In the second switching scheme, when a failure occurs in a path through which a video content is being transmitted and received, the path for receiving the video content is changed to another path in order to prevent interruption of video distribution.
Thanks to the recent progress in the information technology (IT), the broadcasting system is now in a shifting phase to an Internet Protocol (IP)-based broadcasting system. Hence, IP networks are used in many cases to distribute video contents inside and outside of broadcasting stations. This trend is described in, for example, “The Journal of The Institution of Image Information and Television Engineers, VOL. 67, NO. 5, (2013) ‘Broadcasting Facilities and Operations’” (Naohiro Sudo, Hidenori Ishida, Akira Hotta, Tomomi Fukazawa, Tsukuru Kai, and Hitoshi Yanagisawa). In these IP-based broadcasting systems, video signal is IP packetized to be transferred using the Real-time Transport Protocol (RTP). Thus, creating a broadcasting system in the form of an IP-based broadcasting system requires a video transmission system designed for use in an IP network.